In vehicle operation, a vehicle operator needs to obtain different information regarding the vehicle, such as speed, RPM, fuel level, navigation, and the like.
A head-up display (HUD) system is mounted inside the vehicle, and is used for visually presenting such information to the vehicle operator. In the HUD, this information is projected, typically using an image source (IS), onto an optical combiner, which is a semi-reflecting glass, set to reflect light rays projected thereon, and to transmit light rays passing there through. The optical combiner is placed in the field of view of the vehicle operator, between the vehicle operator and the vehicle front window.
The optical combiner reflects the projected visual information to the vehicle operator, while passing through or transmitting the outside scene view coming through the front window. This way, the vehicle operator observes the scene in front of the vehicle clearly, and also sees the vehicle related information on the optical combiner. When the HUD is not in use, the optical combiner is moved to a position, where it is out of the viewing path of the vehicle operator.
In the vehicle, a state of emergency may occur, when the vehicle is traveling forward, and suddenly decelerates. Such emergency states are, for example, a rough landing of an aircraft, a rapid breaking of a car, or an impact with another vehicle. When the vehicle moves forward, and decelerates, the vehicle operator naturally accelerates forward. If a HUD, which is mounted in the vehicle, is in an operating position, and the optical combiner is located in front of the head of the vehicle operator, there is an immediate danger of injury to the vehicle operator, by impacting the optical combiner.
When a HUD system is to be installed in a vehicle (e.g., an aircraft), the projector should be adjusted with respect to the optical combiner, such that projected images shall be aligned with the outside view of the vehicle operator (e.g., the pilot). For this purpose, a telescope is positioned in place of the projector. The position and orientation of the telescope is then adjusted, according to a target image placed in front of the vehicle. Once the desired orientation is achieved, the telescope is removed, and instead the projector is positioned in the same orientation. It is thus desirable to maintain the orientation of the telescope, when positioning the projector, in order to assure proper operation of the HUD. Methods for maintaining the desired orientation when positioning the projector are known in the art.
HUD assemblies are known in the art, and include mechanisms for moving the optical combiner between an operating position and a retracted position, as well as mechanisms for preventing injury to the vehicle operator in emergency situations.
U.S. Pat. No. 5,381,267 issued to Woody, and entitled “Moveable Head-Up-Display (HUD) Combiner Assembly Including Locking Linkage Mechanism”, is directed to a HUD combiner assembly, which includes a four bar linkage for supporting a HUD combiner for movement between an upper storage position and a lower operating position. The HUD assembly is mounted inside an aircraft. The HUD assembly includes a combiner and a four bar linkage. The four bar linkage includes a first fixed link, a second moveable link, a third moveable link, a fourth connecting link and a handle.
The optical combiner is fixedly connected to the third moveable link of the four bar linkage. One end of the fixed link of the four bar linkage is fixedly connected to the ceiling of the aircraft, in which the HUD is mounted. The other end of the fixed link is pivotally connected to one end of the second moveable link. The second movable link is further pivotally connected to one end of the connecting link. The other end of the connecting link is pivotally connected to the third moveable link. The third moveable link is further pivotally connected to the first fixed link. The handle is attached to the second movable link.
When the combiner is in a storage position, the pilot of the aircraft pulls the handle downward. This causes the second moveable link to rotate clockwise, and the connecting link to rotate counter-clockwise. After the second moveable link and the connecting link rotate a predetermined amount relative to the storage position, the third moveable link is also set to rotate clockwise. The pilot pulls the handle further downward, until the combiner reaches the operating position. As the operating position is reached, the assembly is locked in place, using a locking mechanism. The locking mechanism is also used to release the assembly from the operating position, and locking it in the storage position.
U.S. Pat. No. 6,301,053 B1 issued to Cheesman, and entitled “Combiner Assemblies”, is directed to an assembly for mounting an optical combiner as a head up display, on the roof structure of an aircraft flight deck. The combiner assembly includes an optical combiner, a housing and a mounting assembly. The mounting assembly includes a first arm, a second arm, a first release mechanism and a second release mechanism.
The optical combiner is pivotally attached to one end of the first arm and to one end of the second arm, at two different pivot points. The other end of the first arm and the other end the second arm are pivotally attached to the housing, at two different pivot points. The first release mechanism and the second release mechanism are mounted on the first arm. The pivot points on the housing and on the optical combiner are arranged in such a manner, that the first arm and the second arm are positioned in a non-parallel form. The optical combiner is arranged to rotate around the housing between a deployed position and a stowed position.
When the optical combiner is in the deployed position, a user operates the first release mechanism to release the optical combiner, and moves the optical combiner toward the stowed position. As the combiner rotates around the housing, the mean distance between the combiner and the housing varies. The second release mechanism locks the combiner in the stowed position.
Once the optical combiner is in the stowed position, the user operates the second release mechanism to release the optical combiner. The combiner then falls under gravity and rotates around the housing until it reaches the deployed position. The first release mechanism locks the combiner in the deployed position. When moved from the stowed position to the deployed position, the combiner traverses a path similar to the one followed when moving from the deployed position to the stowed position.
While the optical combiner is in the deployed position and the user moves forward and impacts the combiner, the combiner rotates further about the pivot point connecting the housing and the first arm. When the combiner reaches a forward position, it is stopped by a detent arrangement. The user returns the combiner to the original deployed position, by releasing the detent.
U.S. Pat. No. 6,618,203 B2 issued to Nakamura et al., and entitled “Device for Supporting Combiner for Use in Vehicle Display System”, is directed to a supporting device for an optical combiner in a head-up display system, attached to the ceiling of a passenger room of a vehicle. The supporting device includes a base member, a first arm, a second arm, a third arm and an optical combiner.
The base member is directly attached to the ceiling of the passenger room of the vehicle. One end of the first arm is pivoted to the base member at a first point. One end of the second arm is pivoted to the base member at a second point, separate from the first point. The other end of the first arm is pivoted to one end of the third arm. The other end of the second arm is pivoted to the other end of the third arm. The optical combiner is fixedly attached to the first arm, such that it is parallel to the first arm. The distance between the two pivot points on the base member, is equal to the distance between the two pivot points of the third arm.
The supporting device is used for moving the optical combiner between a folded state, where the HUD is not used, and a developed state, where the HUD is used. When the optical combiner is in the developed state, the first arm forms an oblique angle with the base member, such that the optical combiner is in the line of sight of the vehicle driver. The second arm and the third arm are developed in such a manner, that they form a common straight line, coupling the other end of the first arm and the second pivot point on the base member.
When the driver moves the combiner to the folded state, the second arm and the third arm are folded against each other by the pivot point connecting them, and are lifted to a position parallel to the base member. The first arm is also lifted up to a position, where it is parallel to the base member. Since the combiner is fixedly connected to the first arm, it is also lifted up to a position parallel to the base member, and out of the view of the driver.
U.S. Pat. No. 6,078,428 issued to Rambert et al., and entitled “Fastening of a Support for On-Board Equipment”, is directed to a device for fastening a support of a head-up collimator in an aircraft, to the inner body of the aircraft. The support attaches to the aircraft by a plurality of bolts and screws. The device includes a centering block and a centering pawl, one of which is connected to the aircraft, and the other is connected to the support. The centering block includes a positioning aperture therein, in which the centering pawl is housed. The centering block includes a cup. The pawl is inserted into the cup, in the desirable orientation, and the cup is filled with resin. The resin (which is a non-shrinkable rigid bonder, such as an epoxy bonder) then solidifies around the pawl, forming a positioning cavity in the shape and orientation of the centering pawl.
The end of the centering pawl, which comes in contact with the bonding resin, undergoes adhesive-proof surface treatment, such that the resin does not bond to the pawl. The centering pawl is thus removable from the resin-filled cup, leaving a positioning aperture in the resin. Once the pawl is removed from the cup, the support can be dismounted from the aircraft, by releasing the bolts and screws. After dismounting, the support can be mounted again on the aircraft by placing the centering pawl in the positioning aperture of the resin, and tightening the fastening bolts and screws. The orientation of the support is thus maintained as the orientation before dismounting.